• Title, Summary, Keyword: Constraint

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Photometric Stereo Calibration using Constraint on Light Source Directions (광원 방향에 대한 제한조건을 이용한 Photometric Stereo Calibration)

  • Jeong, Seong-Cheol;Nguyen, Viet Hung;Won, Sang-Chul
    • IEMEK Journal of Embedded Systems and Applications
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    • v.8 no.2
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    • pp.111-119
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    • 2013
  • This paper proposes one method on photometric stereo calibration using the constraint on light source directions in which the light sources have the unknown tilt and slant angles but the slant angles are the same. First, the constraint is analyzed based on the equation of linear ambiguity which leads to the conclusion that another constraint should be added to solve the calibration completely. Later, the combination of constraint on light source directions and the constraint that there exists at least six surface patches having known albedos is exploited to resolve the linear ambiguity up to an accurate and close-form solution. The effective performance of the proposed method is demonstrated through experiment results.

Exponential Stability and Feasibility of Receding Horizon Control for Constrained Systems (구속조건이 있는 시스템에 대한 이동구간제어기의 지수 안정성과 실현 가능성)

  • Jae-Won Lee;Wook Hyun Kwon
    • Journal of Institute of Control, Robotics and Systems
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    • v.4 no.5
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    • pp.567-573
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    • 1998
  • 본 논문에서는 입력과 상태변수에 hard constraint가 있는 이산시간 시스템에 대한 새로운 이동구간 제어기를 제안한다. 제안된 이동구간제어기가 terminal ellipsoid constraint를 이용하여 지수 안정성(exponential stability)을 보장함을 보인다. Feasibility를 증가시키기 위하여 시스템을 안정 모드와 불안정 모드로 바꾸는 방법, constraint를 완화하는 방법을 제안한다. Constraint를 완화할 때 constraint를 만족시키지 못하는 부분의 성능을 개선시키는 방법을 제안하고 예제를 통해서 몇 가지 제안한 방법들을 비교한다.

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An Integration of Local Search and Constraint Programming for Solving Constraint Satisfaction Optimization Problems (제약 만족 최적화 문제의 해결을 위한 지역 탐색과 제약 프로그래밍의 결합)

  • Hwang, Jun-Ha
    • Journal of the Korea Society of Computer and Information
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    • v.15 no.5
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    • pp.39-47
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    • 2010
  • Constraint satisfaction optimization problem is a kind of optimization problem involving cost minimization as well as complex constraints. Local search and constraint programming respectively have been used for solving such problems. In this paper, I propose a method to integrate local search and constraint programming to improve search performance. Basically, local search is used to solve the given problem. However, it is very difficult to find a feasible neighbor satisfying all the constraints when we use only local search. Therefore, I introduced constraint programming as a tool for neighbor generation. Through the experimental results using weighted N-Queens problems, I confirmed that the proposed method can significantly improve search performance.

Design of a Robust Controller Using Genetic Algorithms and LMI Design Method (유전자 알고리즘과 LMI 설계 방법을 이용한 강인 제어기의 설계)

  • Lee, Moon-Noh;Lee, Hong-Kyu
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.7
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    • pp.619-624
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    • 2011
  • This paper presents a controller design method for a robust control problem with multiple constraints using genetic algorithms and LMI design method. A robust $H_{\infty}$ constraint with loop shaping and pole placement is used to address disturbance attenuation with error limits and desired transient specifications, in spite of the plant uncertainties and disturbances. In addition, a loop gain constraint is considered so as not to enlarge the loop gain unnecessarily. The robust $H_{\infty}$ constraint and pole placement constraint can be expressed in terms of two matrix inequalities and the loop gain constraint can be considered as an objective function so that genetic algorithms can be applied. Accordingly, a robust controller can be obtained by integrating genetic algorithms with LMI approach. The proposed controller design method is applied to a track-following system of an optical disk drive and is evaluated through simulation results.

Muli-path Constraint-based Routing Algorithms for MPLS Traffic Engineering (MPLS 트래픽 엔지니어링을 위한 다중경로 Constraint-based 라우팅 알고리즘)

  • Lee, Jae-Young;Kim, Byung-Chul
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.5B
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    • pp.508-519
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    • 2004
  • This paper proposed two multi-path constraint-based routing algorithms for Internet traffic engineering using MPLS. In normal constraint-based shortest path first (CSPF) routing algorithm, there is a high probability that it cannot find the required path through networks for a large bandwidth constraint that is one of the most important constraints for traffic engineering, The proposed algorithms can divide the bandwidth constraint into two or more sub-constraints and find a constrained path for each sub-constraint, if there is no single path satisfying the whole constraint. Extensive simulations show that they enhance the success probability of path setup and the utilization of network resources.

A Study of the Value of Travel Time Reliability (통행시간 신뢰성 가치에 관한 연구)

  • Cho, Hanseon
    • International Journal of Highway Engineering
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    • v.15 no.4
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    • pp.155-165
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    • 2013
  • PURPOSES : Benefits for improvement of travel time reliability obtained from construction of new highways should be considered as a major factor in the feasibility study for highway constructions. The purpose of this study is to develop a method of estimation for the value of travel time reliability. METHODS : Highway type (urban/rural highway) and traffic flow type(interrupted/uninterrupted) was considered to estimate he value of travel time reliability. And Double-bounded Dichotomous Choice among Contingent Valuation Method(CVM) was applied to survey the willingness-to-pay of drivers when travel time reliability is improved. Finally the value of travel time reliability was estimated using the results of survey and logit model. The value of travel time reliability was estimated considering travel objectives, time constraint travel and non-time constraint travel. RESULTS: The value of travel time reliability of business trip is higher than that of non-business trip. The value of travel time reliability of time constraint travel is higher than that of non-time constraint travel. The value of travel time reliability in urban area is higher than that in rural area. CONCLUSIONS: It was concluded that the proposed method in this study is more realistic and proper to estimate the value of travel time reliability because it reflects the situations of time constraint travel and non-time constraint travel.

Blocking-Artifact Reduction using Projection onto Adaptive Quantization Constraint Set (적응 양자화 제한 집합으로의 투영을 이용한 블록 현상 제거)

  • 정연식;김인겸
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.40 no.1
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    • pp.79-86
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    • 2003
  • A new quantization constraint set based on the theory of Projection onto Convex Set(POCS) is proposed to reduce blocking artifact appearing in block-coded images. POCS-based postprocessing for alleviating the blocking artifact consists of iterative projections onto smoothness constraint set and quantization constraint set, respectively. In general, the conventional quantization constraint set has the maximum size of range where original image data can be included, therefore over-blurring of restored image is unavoidable as iteration proceeds. The projection onto the proposed quantization constraint set can reduce blocking artifact as well as maintain the clearness of the decoded image, since it controls adaptively the size of quantization constraint set according to the DCT coefficients. Simulation results using the proposed quantization constraint set as a substitute for conventional quantization constraint set show that the blocking artifact of the decoded image can be reduced by the small number of iterations, and we know that the postprocessed image maintains the distinction of the decoded image.

A Study on Development of Measurement Tools for Word-of-Mouth Constraint Factors - Focusing on SNS Advertising - (구전 제약요인 측정도구 개발에 대한 연구 - SNS 광고를 중심으로 -)

  • Yun, Dae-Hong
    • Management & Information Systems Review
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    • v.38 no.2
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    • pp.209-223
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    • 2019
  • The purpose of this study was to stimulate the online word-of-mouth advertising by developing the concept of word-of-mouth constraint factors and measurement tools in connection with the SNS advertising on social networks. To achieve the objective of this study, this study was conducted in 3 phases. First, the exploratory investigation(target group interview, in-depth interview, and expert interview) was performed to determine the concept and scope of the word-of-mouth constraint based on literature study and qualitative investigation method. Second, the reliability and validity of the measurement questions were verified through the survey in order to refine the developed measurement items. Third, the predictive validity of measurement items was verified by examining the relationship with other major construct concept for which the developed measurement items were different. Based on the results of study, 6 components and a total of 23 measurement questions for those components were derived. Each was called intrapersonal and interpersonal constraint(psychological sensitivity, compensatory sensitivity, and other person assessment), structural constraint(reliability, informativity, and entertainment). We developed the measurement questions related to word-of-mouth constraint based on qualitative study and quantitative study and holistically examined the social and psychological, environmental interruption factors acting as the word-of-mouth constraint factors for SNS advertising in terms of SNS achievements and evaluation from the perspective of word-of-mouth constraint. The results will lead to creation of basic framework for systematic and empirical research on the online word-of-mouth constraint and to achievement of effective SNS word-of-mouth advertising.

APPLICATION OF CONSTRAINT LOGIC PROGRAMMING TO JOB SEQUENCING

  • Ko, Jesuk;Ku, Jaejung
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.617-620
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    • 2000
  • In this paper, we show an application of constraint logic programming to the operation scheduling on machines in a job shop. Constraint logic programming is a new genre of programming technique combining the declarative aspect of logic programming with the efficiency of constraint manipulation and solving mechanisms. Due to the latter feature, combinatorial search problems like scheduling may be resolved efficiently. In this study, the jobs that consist of a set of related operations are supposed to be constrained by precedence and resource availability. We also explore how the constraint solving mechanisms can be defined over a scheduling domain. Thus the scheduling approach presented here has two benefits: the flexibility that can be expected from an artificial intelligence tool by simplifying greatly the problem; and the efficiency that stems from the capability of constraint logic programming to manipulate constraints to prune the search space in an a priori manner.

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Constraint Satisfaction and Uncertain Knowledge (제약 조건 만족과 불확실한 지식의 처리)

  • Shin, Yang-Kyu
    • Journal of the Korean Data and Information Science Society
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    • v.6 no.2
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    • pp.17-27
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    • 1995
  • We propose a framework for representing and processing uncertain knowledge on the basis of constraint satisfaction. A system of equations and/or inequalities can be considered as a set of constraints that should be solved, and each constraint in the set is transformed into a corresponding logical formula which can be solved through a constraint solving program. Most of rule-based systems, for instance, use a simple probabilistic theory in order to maintain uncertain knowledge, therefore uncertain knowledge can be represented and processed in the constraint satisfaction program quite efficiently.

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